The overall goal of this proposal is to define from in vitro studies the optimal primate cell-trophic agent delivery system that can be applied to clinical treatment of central nervous system (CNS) disorders such as Parkinson's disease. Previous studies have shown that primate adrenal medulla, a candidate transplant tissue, can be maintained and phenotypically altered in vitro and in vivo when cocultured with cells that produced neurotrophic factors. Therefore, in these proposed studies, primate Schwann cells from several sources will be examined for specific neuronotrophic factors in a bioassay with chromaffin cells, by immunoblots and by in situ hybridization for growth factor(s) messenger RNA. Immortalized primate Schwann cells will be generated by gene transfer techniques to obtain a tissue culture stock of growth factor secreting cells. These cells will be assessed for continued growth factor production and used as donor cells, with or without chromaffin tissue, for transplantation by Dr. Don Gash into the CNS of 6-hydroxydopamine-treated rats, the rodent model of Parkinson's disease. The gene for the neurite promoting component of acidic fibroblast growth factor (afgf1) will be inserted into primate cells to provide an autocrine source of differentiating agent. Chromaffin cells, as well as other candidate primate cells transfected with afgf1 gene, will be monitored for release of this trophic factor by coculture with primate chromaffin cells. Moreover, the effect of specific cytokines and macrophage derived factors on the major histocompatibility antigen expression and survival of chromaffin cells and Schwann cells will be assessed to begin to understand the potential problems of the host immune system. Immortalized cells in particular will be examined as they offer potential, as stated, as a stock of cells for transplantation. Primate chromaffin cells will also be exposed to varying doses of levodopa to establish the effect of post- surgery drug therapy on transplanted chromaffin cells. Ultimately, these studies will provide the optimal donor cell trophic agent system that can be applied as corrective therapy in degenerative CNS disorders such as Parkinson's disease.